Method of casting in a centrifugal mold



April4, 1939. H. wEHMl-:lER ET AL 2,152,717

METHOD OF CASTING IN A CENTRIFUGL MOLD" lFiled Deo. 22, 1937 A n llllllu'nnu, v

.patented A,... 4, 1939i l 2,152,717

UNITED sTATEs PATENT oFElc-E METHOD OF CASTING IN A CENTRIFUGAL MOLD Hermann Wehmeier and Wolfram Ruff, Wetzlar, Germany, assignors, by mesne assignments, to Centrifugal Pipe Corporation, Jersey City, N. J., a corporation of Delaware Application December 22, 1937, Serial No. 181,168

In Germany'DecemAberZl, 1936 2 claims. (olaz- 201) This invention relates to apparatus for, and an The method of the invention is particularly improved method of, centrifugally casting pipe adapted for the casting of pipe in cooled metallic and particularly to the centrifugal casting of iron centrifugal molds. It may, however, be applied pipe. In accordance with the method of the into centrifugal casting in other types of centrifu- 5 vention a powdered material is sprinkled or othgal molds such as sand or refractory lined molds. 5

erwise suitably applied in a thin layer on the The method is particularly advantageous in the upper surface ofthe molten metal asit is being manufacture of small diameter pipes, although'it fed into the mold, and the stream of molten may be practiced with equal advantage in the metal is so guided as it enters the mold that the centrifugal casting of large-diameter pipes.

upper surface or stratum thereof upon which the In practicing the method of the invention in 10 powdered material was deposited is brought into casting iron pipe, a suitable inert powdered macontact with the mold. In the casting of iron terial, such as powdered sand or infusorial earth, pipe, for example,.the layer or stratum of mateor a reactive metallic material such as ferrorial in contact with the mold suppresses or presilicon, manganese-silicon, ferro-phosphorus, or

l5 vents the chilling of the iron. calcium, magnesium or aluminum alloys may be 15 The apparatus of the invention comprises used. Ferro-silicon is especially efficacious both means in combination or cooperation with a cenfrom a standpoint of technical and economical l trifugal casting'machine of the type in which considerations. In using a metallic or reactive the pouring trough` is relatively displaceable with material, for example, ferro-silicon, an especially respect to the mold, for sprinkling powdered maintense effect on the casting is obtained, pre- 20 terial onto the upper surface of the metal as lt sumably due to the preheating of the ferro-sillflows through the trough into the mold. The incon powder during its floating on the surface vention alsoincludes an improved pouring trough of the molten iron which causes the reaction having a laterally deflected spout which is so velocity to be considerably increased. It is posshaped that the uppermost stratum of metal sible, when using powdered ferro-silicon, to cast 25 flowing through the trough is brought into coniron pipe in water-cooled centrifugal molds havtact with the mold, forming the outer portion of ing an inner diameter of 40 mm. and a wall thickthe pipe andthe remaining portion of the metal ness of '4 mm. that are grey throughout their forms the inner portion of the' pipe. entire cross-section.

The method of the invention is particularly The powder should be very ne because'the 30 adaptable to those centrifugal operations in finer the powder, the better it floats upon the which the material to be cast is supplied by means molten metal in the pouring trough. When an of a, trough which has relative displacement beinert material, or`a coarse reactive metallic matween the trough and mold. In such operations.' terial are used, the, powder remains as such on the powder is applied as by' sprinkling a thin the surface of the metal and is brought into 35 layer on the surface of the molten metal, for exdirect contact with the mold, in effect, lining the ample, cast iron, .as it flows along the trough mold with a coating of the powder, If the powder and into the mold. The sprinkling may be effectis a substance which reacts chemically with the ed by any suitable mechanical means which is iron such as ferro-silicon it may be sufllciently 40 preferably mounted outside of the mold. The fine that it dissolves in or reacts with the iron 40 apparatus may be mounted on or adjacent the before the iron contacts the mold. pouring trough or on that part of the machine In the-accompanying drawing, which carries the mold. Figure 1 is a longitudinal section through a In order that the stream of metal issuing from centrifugal pipe-casting machine provided with the trough, or spout of the trough, may contact. means for practicing theinventlon; 45

the wall of the mold with its uppermost, powder- Figure 2 is a section along line 2-2 of Figcarrying stratum first, it is advantageous to conure l. structthe discharge spout of the pouring trough The mold l is rotatably mounted in a longiin a particular manner, for example, by means tudinally displaceable carriage 2. The pouring of a prominent rounding-off of the overflow edge trough 3 extends into'the mold, has an inner 50 of the spout, so as to bring about a deflection of refractory lining 4, and is mounted on a transthe metal stream sideways and downwardly, in versely movable casting carriage 5 which car- Which event the lowermost stratum of the stream ries a pouring funnel 6 for feeding metal 1 into can be deflected relatively to the uppermost the pouring trough.

stratum. The powder-sprinkling mechanism comprises 55 a supply receptacle 8, a spreader orsprinkling device 9 and is mounted in such a way that the falling particles of powder are deposited upon the upper surface of the stream of metal 1 flowing along the trough 3 on its way into the mold I. The sprinkling mechanism may occupy a xed position relatively to the trough, i. e. it may ,be rigidly connected with the casting carriage. It may, however, also be attached to carriage 2 so as to participate in its longitudinal displacement, in which -case the distance over which the powder is carried becomes progressively smaller. At its discharge end, the trough 3 has a discharge spout I0 bent sideways and downwardly in the direction of rotation of the 'mold indicated by arrow Il. The overlow edge I2 of the discharge spout is L.well rounded ot.

pipe being chilled.

, We claim:

l. In a method of casting pipe in a centrifugal I intoy the mold, and guiding the stream of molten metal into the mold in such manner that the ysaid stratum on which the powdered material was deposited is brought into contact with the inner surface of the mold.

2. In a method of casting iron pipe in a centrifugal mold in which the metal is poured into the mold by means of a trough which is relatively displaceable with respect to the mold, the improvement which comprises applying powdered material including silicon to the uppermost surface of the metal in the trough, and then guiding the stream of molten 'metal in such manner that the upper stratum thereof on which the powdered material was deposited is brought into contact with the 'inner surface of the mold, thereby causing the said stratum to form the outer surface of the pipe. 

